1. Technical Field of the Invention
The present invention relates generally to a mobile robot executing a given operation on workpieces supplied to a production line, an automatic production system using the robot, and a robot system actuating a mobile robot disposed at a workstation by downloading a required operation program thereto.
2. Background Art
Recently, production systems using mobile robots have been proposed which feature multi-workability of the robots and ease with which the production ability is changed by changing the number of the used mobile robots.
Changing the number of mobile robots to be used as a function of the production, however, causes much time to be consumed in changing a control system in an integrated control device integrally controlling the whole operation of a production system.
It is also difficult for such a production system to cure a failure of part of production facilities properly and quickly. The production system has a weakness in that if the integrated control device is failed, it will cause the whole of the system to be disenabled.
Further, altering a job of the mobile robot and moving the mobile robot to another workstation require changing an operation program stored in a robot controller. In a case where operation programs are stored in a plurality of robot controllers, it is necessary to change the operation programs individually, which is quite inconvenient to an operator.
It is therefore a principal object of the present invention to avoid the disadvantages of the prior art.
It is another object of the present invention to provide a mobile robot which enables a production line to be constructed easily according to the production while assuring the reliability and a production system using the same.
It is a further object of the invention to provide a robot system capable of altering an operation program for a mobile robot working at a given workstation on a production line easily.
According to the first invention of this application, there is provided a mobile robot executing a given operation on a workpiece supplied to a workstation is provided. The mobile robot includes: (a) a neighboring robot condition information collecting circuit collecting first information on an operating condition of a second mobile robot placed around said mobile robot; (b) a work information collecting circuit collecting second information on flow of workpieces on a production line; and (c) an action determining circuit determining an action based on said first and second information. This enables the mobile robot to determine its action so as to improve the efficiency of production based on operating conditions of neighboring mobile robots and flow of workpieces on a production line.
According to the second invention of the application, there is provided a production system which comprises: (a) a production line having a plurality of workstations at each of which one of processes is performed; (b) a transportation mechanism transporting a plurality of workpieces along said production line; and (c) a plurality of mobile robots. Each of the mobile robots executes a given operation on the workpiece transported by said transportation mechanism at an assigned one of the workstations and includes a neighboring robot condition information collecting circuit collecting information indicating whether another of the mobile robots is placed at the neighboring workstation and a determining circuit determining a process to be executed by the each of the mobile robots based on the information collected by said neighboring robot condition information collecting circuit.
In the preferred mode of the invention, said action determining circuit may determine a process to be executed by each of the mobile robots based on the information collected by said neighboring robot condition information collecting circuit.
Said action determining circuit may determine whether each of the mobile robots should be moved to another process or not based on the information collected by said neighboring robot condition information collecting circuit.
Each of the mobile robots further includes a work information collecting circuit collecting information on flow of the workpieces at the neighboring workstations. Said action determining circuit may determine whether a corresponding one of the mobile robots should be moved to another process or not based on the information collected by said work information collecting circuit.
Said action determining circuit may determine the process to be executed by a corresponding one of the mobile robots according to degrees of priority of said plurality of processes.
According to the third invention of this application, there is provided a robot system which comprises: (a) a storage circuit storing a plurality of operation programs for carrying out processes at workstations provided on a given production line; (b) a first transmission device transmitting workstation position signals each indicating a position of one of the workstations; (c) an output circuit responsive to each of the workstation position signals to output a corresponding one of the operation programs stored in said storage circuit; and (d) mobile robots each receiving one of the operation programs outputted from said output circuit corresponding to an assigned one of the workstations to take action according to the one of the operation programs.
In the preferred mode of the invention, said transmission device transmits each of the workstation position signals when one of the mobile robots is turned on at a corresponding one of the workstations.
Said output circuit is mobile communication equipment.
According to the third invention of this application, there is provided a method of taking measures against a change in production in production line including workstations at a given one of which a first mobile robot 1 is placed to carry out a given operation. This method comprises: (a) a first step of placing a second mobile robot at a selected one of the workstations of the production line according to an increase in production; (b) a second step of collecting first information on an operating condition of the first mobile robot; (c) a third step of collecting second information on flow of workpieces on said production line; and (d) a fourth step of determining an operation to be executed by the second mobile robot based on said first and second information.
In the preferred mode of the invention, the method further comprises a fifth step of selecting one of a plurality of operation programs corresponding to the operation determined in said fourth step and a sixth step of executing the selected one of the operation programs to work the second mobile robot.
The method may further comprise a fifth step of transmitting a request signal requesting an operation program to be performed by said second mobile robot at the workstation at which the second mobile robot is placed and a sixth step of outputting the operation program in response to said request signal. Said fourth step may initiate a download of the operation program outputted in said sixth step to said second mobile robot to work said second mobile robot according to the downloaded operation program.